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Eating at roughly the same times each day may improve things like blood sugar control and appetite regulation.

Caffeine can modify circadian rhythms and could help you adjust to new time-zones more quickly if used intelligently. If you’re flying west, for instance, you might try consuming some caffeine late in the day to speed synchronization to the new time-zone.

Considering your chronotype can help you optimize your diet according to your own circadian biology.

Shortened eating windows can be useful, but aren’t for everybody.

INTRODUCTION

In Parts 1 and 2 of this series, we set the stage for this post by exploring some important roles of diet in circadian system function and metabolic health.We focused in particular on diet timing.

In this final installment, I’ll first touch briefly on the importance of consuming foods and drinks at consistent times from one day to the next. Next, we’ll consider some commonly consumed dietary compounds that influence the circadian system. Then, I’ll leave you with some key takeaways that you can immediately put to practice in your pursuit of better health.

Finally, if you would like to learn even more about the topics addressed here, Dan, Jeff Rothschild, and I did a podcast together discussing aspects of chrononutrition. You will find that here (with youtube link below).

Being consistent in when you eat is a crucial determinant of how you metabolize what you eat.

As we explored inPart 1, a shortened eating window can shift the timing of peripheral clocks without influencing timing of the central clock in the brain. Again, the central clock is mostly responsive to patterns of light and darkness sensed by the eyes. So, a fixed 12 hour eating window during a period of shifting light exposure patterns (think shiftwork) might be expected to uncouple the timing of peripheral clocks (influenced primarily by diet) from the central clock (influenced primarily by light and darkness) – which could disrupt metabolism. But a shortened eating window actually protected against the obesity-promoting effects of shifts in the light / dark cycle in mice, despite the animals eating a similar amount of food (1). If these findings apply to humans, this could have important implications for shift workers.

Human studies support the importance of consistency too. A good example of this was found in a pilot intervention in eight obese adults, who normally ate in a 14+ hour window. When these adults ate at consistent times (which were self-selected) and kept the duration of their daily eating windows to about 11 hours each day, participants ate less, lost weight, and reported better sleep and feeling more energetic (2). You’ll note that this obviously supports favourable effects of shortened eating windows. But it’s worth noting that neither body composition nor sleep were objectively measured. And the participants may have expected health benefits after receiving detailed presentations on the benefits of a shortened eating window, which could have induced a placebo effect. Remember, simply believing that something will work can have a subconscious influence on other health behaviors as well.

Nevertheless, rigorously controlled feeding studies have also shown the benefits of consistency. A recent study exemplified this nicely, finding that women consuming six meals daily had lower blood glucose responses to a test drink and higher diet-induced thermogenesis in comparison to when they consumed the same diets distributed into a varying number (three to nine) of daily meals (3).

DIETARY COMPOSITION AND THE CIRCADIAN SYSTEM

Substances within the food we eat (from fatty acids to polyphenols) also can influence the molecular clocks in body cells (4) and even behavioural rhythms in some mammals (5). Accordingly, researchers have begun exploring how changes to dietary composition influence various aspects of the circadian system. As but one example, switching participants to a lower carbohydrate diet shifted participants’ cortisol rhythms later (i.e. phase delay) and changed the daily expression of a set of genes involved in energy metabolism and inflammation (6). Intriguing, yes, but the practical relevance of such findings is not yet clear.

Of all common dietary components, alcohol and caffeine deserve special attention. Alcohol can be particularly disruptive to behavioural and molecular rhythms (7, 8), as can ingestion of caffeine at the wrong time. Caffeine has clear ‘chronobiotic’ properties, meaning that it can modify circadian rhythms for better and for worse. For instance, caffeine can prolong the period of the molecular clock in cells, and this may help explain why consuming caffeine in the evening delays the timing of the circadian rhythm in melatonin in humans (9).

And with this knowledge that caffeine influences our bodies’ timing mechanisms, we might infer that well-timed caffeine ingestion could help us adjust to new time zones more quickly (10).

For example, if you flew from New York to San Francisco, the timing of your body systems would have to delay to synchronize to the new light / dark cycle on the west coast. In this instance, consuming caffeine late in the day might help you both speed synchronisation of your body’s clocks to the new time zone as well as make you less sleepy during your first few evenings on the west coast.

Many people are subject to overt circadian system misalignment. About a sixth of people work shifts, for example. But enormous studies are unveiling trends in our sleep habits indicative of widespread subtle circadian system disruption among people with more common work schedules too. As we transition between work and non-work days, our sleep timing and duration tend to shift. And as a result, some of us may be at increased risk of diseases such as obesity (11).

Observational studies are also showing large differences between people in ‘chronotype (12).’ Technically, chronotype is a person’s ‘phase angle of entrainment’ (assessed, for example, by measuring the timing of someone’s core body temperature nadir relative to dawn), but we can simplify this by looking at sleep timing to establish whether someone is more of a ‘morning lark’ or ‘night owl.’ These differences in daily patterns between people emphasize how crucial it is that research participants are studied relative to their own internal clocks, as opposed to the social clock. Blanket recommendations prescribing specific meal times for all are at best misguided when we consider the stark differences in chronotype between individuals.

And yet there isn’t much information available out there about how we should tweak our dietary habits depending on our sleep/wake patterns. With this in mind, let’s now consider how we might begin to tailor our eating habits according to our own patterns.

SOME TENTATIVE RECOMMENDATIONS

I reserve my right to change my mind as new evidence emerges. With that dull disclaimer out of the way, the following recommendations are based on my current interpretation of the literature and a dash of intuition.

Good. It’s fun knowing this information, and it can also be useful. In Part 2, we explored how and why eating more of your food earlier in the waking day may be useful if you are trying to shed excess weight and improve your metabolic health. And now you have a better idea of what early is for your clock, not just the social clock.

EAT EARLY IN YOUR DAY, PERHAPS MOSTLY DURING DAYLIGHT

Assigning a larger proportion of your energy intake earlier in the waking day may be preferable on days when you are less physically active. Additionally, consuming a large proportion of your energy intake around physical activity (on days when you are more active) may encourage the nutrients that you consume to be partitioned favourably (storing carbohydrates as muscle glycogen, for example). Although beyond the scope of this article, your nutritional status before and after you work out can markedly affect how your body adapts to the exercise. A series of interesting recent studies has shown, for example, that exercising after an overnight fast can boost endurance exercise performance in athletes (13). Conversely, exercising without eating is counterproductive to the goals of somebody looking to build muscle.

Let’s think about diet timing relative to sleep. If you are awake when your natural inclination would be to sleep (for example, shortly after waking to an alarm), you may want to wait until you’d normally be awake before eating. In the context of eating patterns relative to the solar day, this probably means eating primarily during daylight, assuming that your circadian system is tightly synchronized with the light / dark cycle and you live near the equator. But if you live further north or south, or if you are a particularly early or late chronotype, then don’t sweat it!

EAT AT CONSISTENT TIMES AND CONSIDER USING A SHORTENED EATING WINDOW

If your goal is to maintain or reduce your weight, you may want to try using a shortened eating window if it suits your lifestyle. Perhaps a good time to try a shortened eating window is when you are surrounded by particularly delectable foods (during Christmas and Thanksgiving, for example). I have used a shortened eating window at Christmas for the last two years (without being a zealot) and have maintained or lost weight in these instances.

Another appropriate time may be if you have a relatively sedentary lifestyle. As we saw in Part 2, people tend to inadvertently eat less when they try a shortened eating window. Because they also tend to move less, this typically doesn’t lead to changes in weight. But (and this is a big but!) some people have jobs or physical conditions that enforce inactivity. If these people spend a lot of time sitting regardless, then maybe a shortened eating window would have favorable effects on body composition in these circumstances. (I’ve used a shortened eating window to good effect while rehabilitating leg injuries that forced a reduction in activity, for example).

Finally, it is worth noting that the liver produces more ketone bodies when a person has gone without food for a sufficient time. Therefore, people trying ketogenic diets for whatever reason might find a shortened eating window useful.

So where might you begin if you want to try a shortened eating window?

A good starting point for most is two to four meals, evenly spaced in a six to twelve hour period that begins one to five hours after waking.

If, for example, you wake at 06:00, you could eat four meals between 07:00 and 19:00, or two meals between 12:00 and 18:00.

A consideration that is sometimes overlooked here is how much food you need. If you are a small person and are not very active, then you will not need much food to maintain your weight. Because of this many people like a shortened eating window, since consuming fewer meals means that each is larger and more satisfying.

Another situation in which a shortened eating window can be particularly handy is when jetlagged. In this exciting era of tremendous technological progress, we may soon be able to dramatically expedite synchronization to new time-zones. In the meantime, I’d generally recommend that you try to gradually shift the timing of your diet as the central clock in your brain and sleep/wake cycle shift after rapid transmeridian travel. You’ll thereby try to keep normal timing relationships between your central and peripheral clocks.

Regardless of how you implement it, try to retain your other habits if you use a shortened eating window so that you can more clearly see how you respond to this practice. And perhaps begin with a longer feeding period. Don’t be that person who tries a six hour feeding period and has an extra four coffees before beginning it!

NOT SO FAST…

And please realize that shortened eating windows are not for everyone. Here are three circumstances in which they may be ill advised:

People who are prone to large fluctuations in circulating nutrients, such as blood sugar. For this reason, people with metabolic diseases like diabetes should perhaps consult their physicians before trying a shortened eating window.

People trying to gain lean body mass as fast as possible.Energy balance is energy intake minus energy expenditure. And some people want to be in a positive energy balance. An active muscular man trying to gain more muscle will need to frequently be in a positive energy balance, for instance, and a shortened eating window could be counterproductive for such a person.

People trying to conceive. It is important to ensure that such people are eating enough to support their reproductive physiology. Related to this, whether men and women respond differently to a shortened eating window will be a fruitful research topic. (Anecdotes of less favourable responses to a shortened eating window in women abound, but have not been substantiated by the scientific community.

OTHER TOPICS FOR OTHER TIMES

Given the endless variety of shift work patterns that are possible, it is beyond the scope of this article to give dietary advice for shift workers. Nonetheless, shift workers experiencing disturbed sleep should realize that they may be more inclined to choose energy-dense refined foods. These people should therefore try to modify their lifestyle and food environment to make healthier choices easier. For ideas on this, read this book.

Another topic for another time is intermittent use of longer fasts (24 hours, for example). These can be therapeutic for a variety of diseases, including hypertension and obesity, and you can expect more on this topic from humanOS in the future.

WRAPPING UP

It is here that I temporarily leave my own clock to try to peer into the future of chrononutrition research. Researchers continue to seek novel dietary chronobiotics, and polyamines have recently emerged as candidates to offset declining circadian system function with age (14). (Polyamines are compounds found in abundance in our diets, and are involved in processes like cell growth and stress resistance.)

But we still need to better understand existing dietary chronobiotics.

What, for example, is the ‘phase-response curve’ of caffeine? That is to say, how do its effects on the circadian system differ when consumed at times of a person’s internal day? Answering this question could have implications for shift workers and people experiencing jet lag.

Knowledge of the circadian system may also inform people developing food products. Breastmilk composition, for example, varies with time of day (15), suggesting that food scientists might want to consider morning and evening infant formulae that differ in nutrient profiles accordingly.

And we of course need to clarify whether factors such as existing health problems influence the effectiveness of different dietary interventions.

I hope you’ve enjoyed this detour into the fascinating world of chrononutrition. This article is by no means exhaustive, of course, and those of you seeking more detailed reviews of the topic may want to read recent reviews (16, 17).

There is great value in optimizing the timing of our behaviours, so we hope that you benefit from this series by using the guidance herein to shape your own health practice.

If you have any questions, comments, or suggestions, please don’t hesitate to get involved in the comments section below. And don’t forget to check out the podcast, where we take a deep dive into circadian physiology, meal timing, time-restricted feeding, and much more!

YOUTUBE

TRANSCRIPT

Jeff Rothschild:

The writing is on the wall as far as I’m concerned. Eat most of your food earlier in the day. Don’t eat too late at night. That’s just some general heuristics to live by.

Kendal Kendrick:

Human OS. Learn. Master. Achieve.

Dan Pardi:

Welcome everybody. Today, we’re going to be talking [00:00:30] about a few interconnected health topics. Intermittent fasting, time-restrictive feeding, meal skipping, circadian biology. We are really going to focus on meal skipping in particular and joining me in this conversation, I have invited two human OS collaborators, Jeff Rothschild, he was the lead developer of our fasting course, and Greg Potter, the lead developer of our course in circadian health and metabolism.

Jeff welcome. Give our audience an introduction to who you are.

Jeff Rothschild:

All right, thanks guys. I’m happy to be here and talk with you too. I’m a registered dietitian. [00:01:00] I’ve done a Master’s degree in nutritional science. I currently work in a private practice setting in Los Angeles, California. A lot of the focus of what I do is with athletes and endurance athletes, but I definitely work with a lot of non-athletes. Fasting has been something I’m interested in for a quite awhile. I’ve published some papers on it, and it’s been of interest both personally and professionally. A lot of people, when appropriate, that I work with, I will include some type of fasting. As we get into it over the next few minutes, [00:01:30] there’s several different types of fasting that have been studied and can be appropriate to use for weight loss, for blood sugar control, and cognitive function these things.

Dan Pardi:

Thanks Jeff, we met a couple of years ago, for the listeners, at the ancestral health symposium. Jeff gave our really great talk about restricting your feeding to a limited period of time within the day. Not eating after dark, and maybe we’ll even get into some of that today.

For now, Greg, shifting over to you, please give our audience an introduction who you are.

Greg Potter:

[00:02:00] Thanks Dan, thanks very much for the opportunity. I’m Greg. I’m in the final year of my PhD at the University of Leeds in U.K. and my project mostly looking at the interactions between sleep, diet and metabolic health in U.K. adults.

Dan Pardi:

Perfect. I think we met over twitter.

Greg Potter:

We did.

Dan Pardi:

Greg was always responding to tweets that I put out there at Human OS under score me, also putting up great material. I think it was when you had finally posted your own paper on nutritional effects and circadian biology that I was [00:02:30] like “Wow, this guy really knows what he’s talking about.” That motivated me to connect further with you, and that started the great collaboration. I’m glad we’re all here today.

This broader subject of eating timing, and meal skipping, I think is one of the hotter topics in health today. It’s really exploded onto the scene over the last few years. There’s still a lot of question remain about what’s good, what’s useful, what’s effective, who’s it right for, and today, I want to focus little bit more on skipping breakfast. That is, I think a really [00:03:00] common way that anybody that who is currently engaging in fasting does it. Of course, people do it in other ways as well. It’s an easy one to do. You wake up in the morning, you’re not that hungry, or even if you are, you just decide to not to have your first meal until some point later in the day, usually around noon. Is that good for us?

Before we get into that, there’s some work that actually shows what regular eating patterns are like. Greg, tell us a little bit about some research in this area. What common eating patterns are for modern day humans.

Greg Potter:

I’d be happy to. A particular relevant study [00:03:30] to this question was published in . Satchidananda Panda was the senior author on it. What they did was they looked at adults in the San Diego area. They used a smart phone app to characterize their eating patterns. For three weeks, people took photos and they could annotate these photos of everything they had to eat and drink. These were time-stamped, so they knew when these events were occurring. The researchers then collected these [00:04:00] photos and the written information afterwards and determined how much they’re eating and when they were eating. Also 47 of those people all wore action watches to look at their physical activity patterns, and when they were sleeping in particular, by doing so they could look at when they were eating, relative to when they were sleeping.

What did they find? They found that on average, people ate over period of nearly 15 hours each day. That time of that is [00:04:30] between the first event that contained calories and final even that contained calories was nearly 15 hours. Only 10 % of the people had an eating duration, or eating period of less than 12 hours. About 23 % of calories were consumed by mid-day and over 35% of calories were consumed after 6 pm.

What else they find? They also looked at whether there was a difference between weekdays and weekends. There’s some research previously [00:05:00] in the congregate biology literature, which hAs looked at three compasses and how they differ in weekdays and weekends. Sleep people timing typically differs on workdays and non-workdays, they’re calling this social jet-lag. So many people will sleep later on weekends and they’ll sleep in on the weekends. As a result, when they go back to work at the start of the working week. It’s like flying a time zone or two to the east. About 69 % of people [00:05:30] experience at least an hour of social jet-lag each week. What they thought was maybe see something similar with people’s eating patterns, and that’s what they found. They found that typically, people consumed breakfast about an hour and five minutes later on weekends, versus weekdays. Subsequently, they then did a study to look at what happens when you take these people with more [inaudible 00:05:54] eating patterns, people who were eating over longer time period, then are asked to eat over shorter [00:06:00] time period. That’s more relevant to today’s question of what happens when you skip breakfast.

Dan Pardi:

To do a little bit of summary, they enroll people into the study, the first part of the study over three week period, they used a smartphone app to collect information on food type calories and the timing. When were those calories coming into the body? Also sleep and activity patterns by the actograph watch. They could look at what was the length of time that calories were being consumed in a person’s what we call “wake period” or the time that they’re a wake. [00:06:30] Lot of these people were maintaining an eating pattern that was about 15 hours long. First calorie in. Last calorie in. Only 10% of people had an eating window, a period when they’re taking in their calories was less than 12 hours.

The second part of the study, they’re now going to do some time restricted feedings. Tell us about that.

Greg Potter:

Yes, it was a small pilot study. Eight people who had eating patterns in which they spread out their eating over at least 14 hours each day were asked to [00:07:00] restrict their eating period to about 10 hours each day, and to keep that period consistent on weekdays and weekends. When I say eating, I mean everything apart from water.

This included five men and three women. First they were given a detailed presentation on the knowing benefits of time-restricted eating. Satchidananda Panda, in particular has done a huge amount of research using rodents, and has found that using this time restricted eating confers [00:07:30] many metabolic benefits. When rodents are given less than healthy diets, which particularly called high-fat diet, but noted to be they were also high sugar diet.

These people, for 16 weeks tried to stick to this 10 hour period. Each week, they were given a feedogram, which is a pictorial display of their eating patterns across the 24 hour day for the previous seven days showing how well they were accomplishing their goals. They weren’t [00:08:00] asked to change the actual quality of the diet at all. There was no information given about what you should eat, or anything like that. The emphasis was purely on when they were eating.

Follow the map for 16 weeks. They measured how heavy they were at that point, and they also gave them subjective self assessments of sleep and how energetic they felt. This is just a Likert-type scale where you rate from zero to ten. How [00:08:30] well you slept the previous week. What they found was that on average, people lost over three kilos during those 16 weeks. They did so by reducing their calories by about 20%. That’s noteworthy, because what they found previously in their rodent research was that time restricted eating causes many metabolic benefits independent of calorie intake. If you restrict eating periods of these rodents, they don’t actually [00:09:00] eat less, but they are protected against obesity. The difference is in humans, they do eat less. The result is that they lose weight. They also felt more energetic and they reported they slept better. They enjoyed doing so so much, all of them, that they chose to continue for the rest of the year there-after, and the researchers then followed up one year after they began. What they found was that they actually retained their weight loss.

Dan Pardi:

This is one of the reasons why the interest in fasting is such a craze right now, because [00:09:30] we’re given complex instructions about what to eat. We’re put on sort of protocol that was very challenging for people to do. First, you have to look at how doable is something. Or perhaps how effective could it be, but then how doable is it. If it was extraordinary effective, but very few people could do it, then it wouldn’t really be effective overall in terms of improving public health.

Weight loss is an enormous importance. These people were put on a 16 weeks intervention. They took in less calories without being told to do so. They opted in to stay on a program for the next year. [00:10:00] They had not only maintained their weight loss, but they also had perceived improvements in their sleep and perceived improvements in energy level. That is really exciting to me.

Jeff Rothschild:

Yes, to jump in a couple of things that I really like from the practical side. I work with people and this is definitely a tool that I look to it. It’s one of the first things I look to is shortening someone’s eating window. The people in that pilot study were at least around a 15 hours was a typical eating window. Unfortunately when someone is already eating in a 10, 11 or 12 hour window, it doesn’t work. You can [00:10:30] crunch it a little bit, but you won’t see- you won’t expect to see the drastic results that you would count from shortening by four or five hours.

Dan Pardi:

Yeah, that’s a really important point.

Jeff Rothschild:

You really have to consider, sticking on the practical side for a minute. If someone typically likes to eat breakfast, they can eat breakfast at 8 am. Then normally eat dinner at 6:30 pm, there’s not a whole lot to work with there.

The other side of it is, people often like to have dinner with their families, or some other social obligations that can tie into where we are going with. The next step then would be to say ” Okay, if I eat [00:11:00] dinner at 7:30 or 8:00 then I should start eating at 12:00, and skip breakfast.”

I think I’m jumping a head a little bit. I want to point out one more really interesting thing, in my opinion about the study, using that app and I think it’s an obvious statement, but smartphones are going to change the way research is done, because once the person took the picture of their food. It was time stamped and sent in, it was erased from their device. What this does is eliminate the possibility of what you might call feedback effect. When you [00:11:30] are looking at a food log, the person might be writing it down and then they might say, “Oh my gosh, I’ve already had this, this and the other thing today, so I better not eat these chips.” or whatever it is. There’s this constant, even if someone is just supposed to be just writing down what they eat without judging it. There’s going to always be that effect. This is a great way to just take a picture, and then it’s done. It can minimize any of these effects.

Dan Pardi:

That’s a really important point. Incidental improvement in dietary quality by this active, you can call it mindfulness by stopping for a moment, taking a photo of your food, [00:12:00] most people are probably going to think about that at the moment, so there could have been improvement in dietary quality simply by the virtue of the way that the study was conducted. Hard to go around that. Like you said, it sounds like they were trying to mitigate that as a possible confound to changing the results by erasing the photo.

Greg Potter:

Two more comments. One is the weight recidivism is clearly a big problem. People typically don’t have a problem losing the weight. It’s a problem they have with keeping the weight off in the long term. It’s interesting that they wanted to stick on and [00:12:30] that it stayed off until the one year mark.

Then the other thing I was going to mention picking up from what you just said then was that diet quality did improve even though they weren’t asked to improve or change their diets. I think one thing to consider there is when people are restricting their eating period, because the researchers didn’t really speak to this. If you look at this supplemental data, you can see individual food items and when they were consuming those food items. What they said is that, because [00:13:00] people restricted their eating period, they didn’t move the items they were eating later in the day which might be less healthy options, and things like alcohol, and late night snacks. They just chose to not eat those at all. I think one thing that’s fairly relevant to future studies of this restricted eating is, what happens when you change the actual timing of the eating periods on people’s food choice.

Dan Pardi:

Right, there could’ve been some aspect of the way the study was conducted, and virtue of taking photos that could have had an effect on the dietary quality of the [00:13:30] participants. Secondary option is that time restricted feeding itself can have an impact on dietary quality. Perhaps by affecting neuro circuits that change what we pursue or are interested in. That is a possibility as well. There’s a study in Jeff’s fasting course where we look at leptin sensitivity and how it’s improved over 24 hour fast. There could be some mechanics that are taking place behind the scenes that are actually helping to improve the food that we pursue –

Dan Pardi:

And or overall appetitive drive, or our drive to eat.

Dan Pardi:

Jeff, you mentioned a really [00:14:00] important point here. If they’re going to do something like this, the easier way to time restrict your eating window is by skipping breakfast, for a lot of people, not for everybody, but dinners tend to be a social event where you’re with friends and family. Breakfast is little more of an independent act, if you will. You can grab or make food before you leave the house. That tends to be an area where one you’ve been on an over-night fast, while you slept, and lot of people aren’t really hungry in the mornings. It’s not very hard for them to try to [00:14:30] extend that window by not eating right away, and then eating a bit later.

Let’s talk about breakfast skipping. Jeff, tell us your thought around what the research says about skipping breakfast. Is it good for us. Are there some consequences to it. What do you think?

Jeff Rothschild:

Such a contentious topic. I think we can look as a good jumping off point from the last study to a recent study by Alessa Nas and their colleagues called “Impact of breakfast skipping, compared with dinner skipping on regulation of energy balance and metabolic risks”. The title says it all. Basically, they’re [00:15:00] comparing what happens, and this is just acute, so one day, whether you skip breakfast or you skip dinner, or have three meals. They used relatively small group, but 17 people, a mix of nine women and eight men. A range of BMIs, 11 people that were normal weight, five, that were overweight and one was under-weight. There was this pretty varied group there. Also, we have this context of regular breakfast eaters versus breakfast skippers.

There was some other research that points to the fact [00:15:30] habitual eaters do better when they eat breakfast and not skip it, and then there are the habitual breakfast skippers. I kind of have my doubts about that, because I think that it is very trainable, and so people that are habitual breakfast skippers, when you’ve given them breakfast long enough, there’s a lot of research from Heather Leidy’s group, in Missouri, that shows that people, especially teens, that habitually skip breakfast, they generally do better, just to keep it general, they do better when they eat breakfast with protein. Anyway to this study, there’s 13 were regular breakfast [00:16:00] eaters and four were occasional skippers. Little bit of a mix, but most people that generally ate breakfast. The interesting thing about the way they designed the study, and there’s always study design questions, the calorie intake was the same on all days. This is pretty important. If you skipped breakfast, some people would argue that well, you’re going to eat less during that day.

Greg, I think you can probably talk what happens when people skip breakfast, and they move less, so it ends up being the no net difference in energy expenditure versus energy intake. This study, they chose to keep the calorie [00:16:30] intake the same. It was either spread through three meals, or through two meals. They measured the energy expenditures as basal metabolic rate, slightly higher on the meal skipping days. I think that’s related to the fact there was larger meals consumed. The same amount of food was spread over two, instead of three meals.

Basically the carb and fat burning, when you skip breakfast, statistically significant more fat and less carbohydrate, but it’s practically negligible. It was about four grams per day of fat difference than 28 grams of carbs per difference. [00:17:00] It’s significant, but honestly practically negligible on a day to day practice.

Dan Pardi:

Right.

Jeff Rothschild:

What they found that is most interesting to me though, is something called postprandial homeostasis model assessment index, which basically measures insulin sensitivity. It’s a calculation based on glucose and insulin, and also looking at glucose concentrations after lunch. They were higher after lunch on the breakfast skipping day, than on the dinner skipping day. What this means is, we’ve seen this in several other papers, breakfast exerts what’s called the second meal effect, and some papers even show a third meal effect, meaning [00:17:30] that breakfast affects how your body processes lunch and potentially dinner. Meaning you have generally better blood sugar control and this is seen both in healthy and people with diabetes. I think this is an argument in favor of eating breakfast even in healthy people.

Dan Pardi:

We should pause for a moment and talk about breakfast. Is breakfast the first meal that you have in the day? Is it a meal that occurs at a particular time of the day? The effect of that meal that influenced by the length of time between your last meal. Whether or not you had dinner later [00:18:00] or earlier or even didn’t have dinner. Now we’re getting more into aspects of circadian biology which is body timing.

Let me collect your thought on this. Greg, I’ll start with you. What do you think breakfast really means? Is it just a first meal of the day, or is it a meal that occurs at a certain time?

Greg Potter:

That’s a very good question, and very good points that you raised.

I think technically, it probably should refer to the first meal that you have during the day after sleeping. You are truly breaking the fast, that actually historically, especially in research, [00:18:30] it’s somewhat arbitrary. That’s been a big problem, I think previously, because particularly in nutritional academiology, people say what did you have for lunch, what did you have for dinner, what did you have for breakfast. There’s no indication as to when that happens, or how long it’s been since the previous meal. Even in these studies, you don’t actually know whether these people always post absorbed when they can consumed breakfast for example. It’s tricky question. I think the first meal of the day though, [00:19:00] probably is the most practical use of the time breakfast. Obviously if you wait until 2 pm to consume your first meal, that probably is your breakfast.

Dan Pardi:

Right.

Jeff Rothschild:

I thought you would say something different based on your background in circadian biology. Technically you’re breaking the fast, and people love to say that as the reason to skip chronical breakfasts and just wait until lunch, and that becomes your breakfast. But, as you know, there are so many interactions, so cortisols, the daily rhythm of cortisol for example, and how that might interact with the first meal. The way [00:19:30] I think about it is I see it as a certain number of hours. I don’t know what that number really should be optimally, but I think of breakfast as morning time as it relates to your body clock. Again, maybe we don’t know the optimal window, but from a practical stand point I don’t see it as the first meal after sleep, but rather something in that window relating to your cortisol and melatonin rhythms and whole symphony that’s going on with your hormones under the hood and foods certainly impacts it. Which is why we see the second meal effects, if really it made no difference, [00:20:00] lunch should be handled completely the same from your body, as far as insulin and glucose goes.

Greg Potter:

I think you are absolutely right, Jeff. As Dan said, some people wake up and they’re not hungry. Often I think the reason is, their sleep artificially has been restricted, so if you use an alarm to wake up, then you’re probably not going to be hungry. I’m not sure in those circumstances that you necessarily should be eating. There’s been some interesting work in recent years looking at roles of melatonin, for example. In glucose homeostasis in particular [00:20:30] and what people have found recently is that if people consume their first meal when they’ve still got a fair amount of melatonin floating through their blood, they’re more insulin resistant than they would be otherwise. That’s probably because they’re roles of melatonin signaling on pancreatic function in particular.

Going back to what you speak about, Jeff. Thing is actually right. If you could look at things relative to circadian phase, that would be very interesting and [00:21:00] useful. You would think about what’s your anchoring point would be. It might the time at which you naturally wake up and when that first meal occurs relative to that time. The problem being that you don’t necessarily know when someone is naturally going to wake up. You could use markers of circadian phase, but in terms of practicalities, that poses problems.

Dan Pardi:

The circadian system is largely trying to prepare the body to be functional for certain activities given previous history. If you are [00:21:30] eating breakfast regularly at 8 am, then the body is going to be prepared for a meal at that time. If it’s a regular exposure. Now if all of a sudden, you are skipping a meal, or couple of days you skip, a couple of days you don’t. That could also have influence on what’s happening behind the hood. Lot of these studies that are looking at breakfast skipping, they tend to be in people that usually are having breakfast. If the component of the study or people that sometimes do skip breakfasts, they’re not looking at people that always skip [00:22:00] breakfast. If you always had your first meal at noon, is your body therefore circadianly speaking, prepared for the ingestion of food substances, which would then had second and third meal effect would be improved. Or you should say glucose response would be less concerning or less abnormal.

Jeff Rothschild:

That makes a lot of sense. If someone does get into that routine, aren’t they constantly effectively jet-lagging themselves? 80 % of our liver genes have a clock and a set response to the food. If someone only ate it- I don’t [00:22:30] know if there are any studies that really look at it from this stand point, but we want a strong robust circadian rhythm that in tune with the life cycle and temperature, the hot and cold, and changes through the day, and the light and dark cycle. We are then dissociating the light and dark from the food cycle. That seems potentially problematic, although it’s all speculation.

Dan Pardi:

There’s lot of questions that remain to be addressed, and Greg, I’ll get your take on this in a moment. I think that if you are eating within the light period, when the sun is out. Then that is different than [00:23:00] eating at night, or to eat at night regularly. I am curious about if you regularly maintain a certain pattern, then does your body adjust to that? And address it in a – what we consider a proficient healthy way. Right now, we are talking about what is the length of time that you are consuming food in the day. How long of a period is no food in your system. When is that window occurring, and next is the actual timing important too? Do you need to take in certain calories at a certain time of day in order for those calories to be handled effectively and subsequent calories to be handled [00:23:30] effectively as well.

Greg Potter:

Couple of thoughts. One is it’s really important to think about someone’s chrono type with this. Chrono type is whether someone is more of a morning lark or night owl. I think the problem with some of these studies is that they often enforce times on people. They’d say, to keep things consistent, you need to consume breakfast at this time, lunch at this time, and dinner at this time. They might be happening at different circadian phases unless they’ve ensured that people have relatively average [00:24:00] chrono typed before hand.

Another thought is that there is good rational for thinking that people’s responses are consistently going to differ according to time of day. For example, we know that diet and the juice thermogenesis higher in the morning. Know that insulin sensitivity is likely higher bit earlier in the day. As I touched on previously, hormones like melatonin do influence postprandial responses. Consuming food when it’s dark outside, [00:24:30] or in a dimly lit environment after your dim light melatonin onset all the time which your body naturally secretes a certain amount of melatonin. That’s likely to influence your responses to eating.

Another thought is, consistency is really important. The degree for which this is dependent on circadian system is a bit unclear. Because many of the studies that are showing the importance of consistency hadn’t looked at it from a [00:25:00] chrono biology perspective. Couple of papers come to mind. There’s a guy at University of Nottingham in the UK in [inaudible 00:25:07]. He’s done some really nice research in this area in recent times. There was a nice cross over study he published last year. I think how he’s saying this first author on it, and what they did is they took women, and they had them consume an identical macro nutrient profile and therefore amounts of energy for two 14 day periods, and there was a 14 day wash out [00:25:30] between these periods. Difference was that in one of those periods, women consumed variable number of meals, so three to nine meals, and in another, they consumed a consistent number of meals. What they found is that those consumed the consistent number of meals had a great thermo effective feedings, and a lower glucose response to standardized test ring. They also found that people were less hungry and everything they found pointed to the importance of consistency.

[00:26:00] These importance recognized that cells throughout our body have their own molecular clocks that are ticking away, always. They’re responsive to different stimuli, and in that way, as you mentioned, they can be uncoupled from each other. The clock in SCN is primarily trained by the light-dark cycle. By trained, I mean being synchronized with the light-dark cycle, whereas the clocks outside the SCN are entrained by other inputs primarily and not from feeding and fasting. [00:26:30] The degree to which they are entrained by feeding and fasting cycles does differ by organ, for example, the lungs and the kidneys might be more responsive to feeding than the liver is, at least in mice.

It’s important to think about that, because many people in circadian biology fields think that un-coupling, eating at inappropriate times is important to those adverse metabolic consequences that you see subsequently. What we don’t have a good handle on [00:27:00] is the degree for which that’s the case, so what is the normal range of phase relationships between these different clocks that can be associated with good health.

Dan Pardi:

The focus at this point of the conversation is on breakfast skipping.

Several of the studies we’ve looked at showed that when someone skips breakfast, they take in more calories later in the day. If you look at the sleep loss literature, you actually see a similar phenomenon. You see that people who get [00:27:30] inadequate sleep tend to eat more calories later in the day. Also, we know that inadequate sleep is a risk factor for weight gain. So the question is, is it the timing of these calories, or is it the impact of time of day on our eating behaviors that could be contributing to the association we see with sleep loss and weight gain. The panda study we discussed earlier when people ate later in the day, it tended to correspond to with over-consumption [00:28:00] for what that individual needed in terms of their own [inaudible 00:28:03] need.

We discussed the metabolic consequences of breakfast skipping. In addition, I highlighted that when we skip breakfast, we take in more calories later in the day, and there could be a tendency to over eat, take in more palatable calories, like desserts.

So Jeff, what other information do we have on breakfast skipping that can inform us to as whether this is potentially a healthy or unhealthy behavior.

Jeff Rothschild:

Yeah, I think I’ve mentioned it briefly, but one of the studies that often comes to mind, and this was in people [00:28:30] with diabetes, but again skipping breakfast significantly increases postprandial hyperglycemia after lunch and dinner. Basically, the people’s blood sugar rises much more after lunch and dinner when they’ve skipped breakfast compared to having a breakfast. Insulin doesn’t work as well. If you look at the insulin curve, it’s a little bit delayed, and a whole lot of things happen that you don’t want to happen when you have diabetes as far as your blood sugar control goes when you skip breakfast. Almost a no-brainer for me there.

To talk about some of the fasting stuff, again, just thinking [00:29:00] in practical use of this stuff, that’s why I really do think of time restricted feeding, shortening your eating windows as probably the go to type of intermittent fasting. I think this is the most promising, and the first tool I look to, because of the circadian rhythm aspect. Alternate day fasting, maybe we can talk about another time. There’s a fair number of good studies using alternate day fasting when that is just as it sounds, people eat normally one day, and then either fast completely the next day, or have about 500 calories. [00:29:30] This consistency is important, even though we don’t know enough about it as much as we want to. It’s pretty clear that having consistent patterns leads to better glucose control and so on. Whenever the window seems to set you up daily consistent pattern, where as alternate day fasting can be effective for weight loss. I’ve always felt it’s putting you out of sync a little bit if you eat one day a lot and the next day, nothing, or 500 calories. I’m excited to see the literature continue coming out and trying different timing and things like that. I think there’s someone [00:30:00] wanting to try some type of fasting, I think time restricted feeding windows is the great first place to go.

Dan Pardi:

That’s great. I think some questions to be resolved would be can you take in calories. Let’s say you have a consistent window, you eat between 10:00 and 6:00 every day. As long as you are eating anytime in that window, whether it’s you’re eating right at 10:00 or you’re eating at noon, or you’re not eating until 2:00, timing of your dinner changes timing of your lunch changes, is that going to be effective? Is your body going to handle [00:30:30] those calories in a manner that we would consider optimally healthy, or do you have the limited eating window and it’s even better, is there room for optimization, or is all the benefit from a meal at 10:00, meal at 1:00 and a meal at 6:00, let’s say.

Greg Potter:

Yeah, the diabetes paper, that was from Floyd’s group, I know that he published some earlier work, maybe in 2013 looking roughly at that question, but not in the context in the time restrictive feeding. They were over-weight women, this is just from [00:31:00] memory, who over 16 weeks or so, consuming weight loss diet. The difference between the two groups was whether they consumed a high proportion of their calories earlier in the day, or later in the day. Those that consumed them earlier in the day had better metabolic outcomes. They lost more weight, they had greater improvement in glucose regulations, and perhaps [inaudible 00:31:23] too. My inclination is probably to think that the same might hold true for the time restrictive [00:31:30] feeding window. Even within that, let’s say you are eating a 10 hour period or 12 hour period, provided that you are not starting it too early, or too late, I suspect that perhaps consuming more early within that window might be favorable.

Also, related to that, one study we didn’t touch on, well two studies, really, from University of Bath, they’ve published very interesting work on what happens when people skip breakfast in both lean people [00:32:00] and the obese people in the last few years. What they found was that if people skipped breakfast, then they do eat less, but they also move around less. What I wonder is, if you have that time restricted period earlier in the day, are you telling your brain, you have energy available you can still move around as per normal such that eventually you could be more likely to be in a negative energy balance at the end [00:32:30] of the day if you consumed your time restricted eating period earlier in the day.

Dan Pardi:

What I find interesting from that study is that energy intake between the breakfast eaters and people that they’re considered fasting, eating their calories afternoon, the difference in calorie intake over the course of the day was 338 calories. It was not statistically significant, but I think in a case here, we could say clinically meaningful difference. If you look at the last 40 years, at least on the population level, most of the weight gain from 1980s [00:33:00] to now, or to the 2010 time was described by a calorie excess of about 350 calories per day. When you think about that, that explains almost all those calories. So yes, there wasn’t changes in weight loss, etc, but I felt that was discrepancy from the amount of calories that we are different between the two groups in terms of what was consumed, and then actually the results of the study. It was a six weeks study. We could’ve seen different results if there was people in the study and it went longer.

Greg Potter:

I think one thing also that’s interesting [00:33:30] is that if people are spontaneously eating less, it might be a better option for someone who is necessarily sedentary. It could be someone who’s injured, or they just have a job for whatever reason, just limits their physical activity. In those circumstances, if they restrict their eating period, then if they inadvertently reduce total amount of foods that they eat, then that’s a good thing.

Dan Pardi:

Speaking about breakfast, which is slightly off topic, but we’re talking about whether or not skipping breakfast is important [00:34:00] or useful or detrimental. We do not in Stephan Guyenne and I, our ideal weight program, we recommend lean weight maintenance program which is a version of a Mediterranean diet. We ask that people try to consume about 25 % of their daily protein at breakfast, because there’s good solid evidence that shows that will impact the calories that people want to consume, so they’ll want to consume less calories over the course of the rest of the day. It’s real opportunity to [00:34:30] have a high protein breakfast to maintain weight.

Other factors matter too. Things like fiber intake has shown similar results in modifying rest of the day calorie intake. Probably one of the most interesting studies to me is, again a bit of a tangent, but really fascinating. Last year, a group gave people high propionate producing inulin as a fiber supplement. They did imaging on the people after a period of time where they had this diet. They found that people responsibility to hyper palatable food was diminished. It made me think of this idea that [00:35:00] the better you eat, easier it is to eat better. What does that mean? What might mean, taking a lot of fiber and protein in the morning, and regardless of the timing of that, that might actually have a favorable effect on weight and metabolism for the rest of the day.

Greg Potter:

Yeah, I think [inaudible 00:35:14] said that too, alternate day fasting studies in particular, if someone is eating just once on those days, then it’s probably worth thinking about changing your macronutrients profile to factor that into the equation too. Because any of the studies [00:35:30] have used the same composition, so it could be 50 % carbs, 30 % fat and 20 % protein, for both those days on which they are eating very little food, and also days they’re eating more food. Maybe on those days whether they’re consuming far less, they need to eat relatively more protein and less fat and carbohydrate.

Jeff Rothschild:

Yeah, I’ll say, again from practical stand point, that’s something I do with people. I don’t often use alternate day fasting, but I’ll use some variation, typically like a five-two, which is out [00:36:00] of two days, not consecutively of 500 calories and absolutely switching the macros like that makes the adherence and the doability of it completely different. It’s so much easier for the person to do.

Dan Pardi:

Speaking of personal experience, I’d notice real effects about what I eat for breakfast, and then what my appetite is like for the remainder of the day, regardless of when I eat it.

Jeff Rothschild:

Yeah, I want to chime in one more thing about it. There was an alternate day fasting study that compared eating that one meal at lunch, or the one meal at dinner, or as three small meals. [00:36:30] They didn’t measure any circadian biology aspects of it, but they found similar weight loss and general changes in blood lipids and blood pressure. They were fairly similar. The conclusion was that it’s whatever works best for that person. I don’t know, again, that you could probably argue or detect something further deeper in there, but in this particular study, that was what they found.

Dan Pardi:

Yeah. I would be remiss not to talk about a study that I mentioned in my Paleo FX talk, but work by Addie [Newfeld-Cohen 00:36:57] out of the Weizmann institute in Israel looked at [00:37:00] the daily pattern of production of certain enzymes that deliver nutrients to the mitochondria and when looking at the protein pyruvate dehydrogenase which determines the rate of glucose utilization for generating energy, she and her group found that mice had the highest amount of this enzyme during sleep which would then suggest that the ability of the mitochondria to burn sugar is greater at that time. Then they thought, “Okay, let’s test this.” When her team supplied the mitochondria with glucose, the metabolism of sugar had to be at its highest level too. [00:37:30] It seemed to process sugars well, at the time when enzymes that deliver sugar substrates to the mitochondria were highest. Now conversely, they also looked at the enzyme, carnitine palmitoyltransferase which is an enzyme that turns fatty acids into mitochondria and she found that this protein was produced the highest rate when the mice were awake, and physically active. They subsequently gave the animals fats, and they were utilized most efficiently during the wake period.

I wouldn’t say this is necessarily happening in humans, but what it does suggest is that our body’s ability to process nutrients, [00:38:00] even of a certain type, is determined by the circadian production of certain enzymes. That adds to this conversation that we’re having. I don’t think it necessarily offers extraordinary clear direction about what we should do, but we know something at play here.

Let’s collect some final thoughts, we talked about a lot of stuff. There’s more that we’ll talk about in the future, because this is a big and important topic. Jeff, since you’ve been studying this for awhile, you work with different clients, and also you’ve personally explored different patterns. What are your thoughts on the subject now? [00:38:30] How would you get somebody started?

Jeff Rothschild:

Yeah, get someone started as far as they’re looking to just improve their health, or weight loss, of course, it depends on where they’re at, and where they want to go. The risk of sounding obvious, but I would generally say, if I needed to give a blanket recommendation from where I see, all the research and everything we’ve talked about today. I think eating breakfast with protein, a good amount of protein, so at least 25 to 30 grams if not more is super important relatively soon – again, I’m going to speak vaguely ’cause we don’t know exactly how many hours after you wake up, but I think relatively within [00:39:00] first hour or two after waking. Eat most of your food when the sun is out.

Now, of course, there’s exceptions. A morning workouts, sometimes I do with athletes I work with, suggest or work with them on doing some fasted endurance exercise. I think there’s absolutely a place for that, but if we’re just talking about general blanket recommendations for good health, and then I do like to stress eating with the sun. In the summer, right now, the sun here is out up until around 8:00, almost 8:30, 9:00 soon. I think people could be pretty cavalier with their food to some degree at this time. [00:39:30] Now in the winter, maybe it’s not a hard stop at 4 pm or 4:30 pm when it gets dark. I think definitely, we’ve mentioned several times now, putting the bulk of your food earlier in the day. I just think there are so much mechanistic and – there’s so much reasonable evidence to support that, even if we don’t have these study saying “yes”. The perfectly designed studies, I mean the writing is on the wall as far as I’m concerned. Eat most of your food earlier in the day, and don’t eat too late at night as some general heuristics to live by.

Dan Pardi:

That’s from the study that [00:40:00] Greg mentioned at the beginning Lepanda, I think closed the forty calories of the day happened in the evening, that’s a bit opposite of a common eating pattern, where the evidence in your mind suggests that we would maybe want to flip flop that and have more of those calories earlier in the day, and fewer in the evening.

Jeff Rothschild:

Absolutely. There’s a slide I often use when I give talks, and the breakfast is a little piece of toast, lunch is a salad and there is kid with giant plate of food in the evening. At that people always laugh, because they recognize it that’s [00:40:30] their pattern. They restrict all day, and then can’t tell you how many times I hear, “I’m just starving at night.” Or- I think flipping that up side down, I think it’s just a smart thing to explore.

Dan Pardi:

I’ll offer a caveat after that. Greg I want your input.

Dan Pardi:

One problem with that method is taking in a lot of calories earlier in the day should homeostatically and metabolically from what we were discussing, encourages us to take in fewer calories later. But so much of our eating patterns not determined by mechanisms that are trying to promote balance within our body, [00:41:00] rather pleasure mediated drives our food intake. You’re maybe not that hungry, but then you sit down to dinner, and you’re served a big plate of food. You’ve been trained to be a plate cleaner. Therefore you’re now over consuming, because you weren’t compensating with your calories earlier in the day. That’s another confound here. Metabolically maybe that makes perfect sense, but for all intense practical purposes that might be more problematic for some, because of the way they eat food. Simply restricting and occasion to eat might be better, just because when they sit down to eat, [00:41:30] they have these ingrained behaviors that are designed to clean the plate regardless of what their body is telling them.

Jeff Rothschild:

Yeah, you’re absolutely right.

Greg Potter:

Completely agree with you guys. Couple more things with the consistency is really important as we discussed. As you mentioned that, I think practicality also is crucial and what needs to be considered is how important different things are to you. Something might be perfect metabolically, not perfect, but it might be superior metabolically, perhaps what you want [00:42:00] is different from that. Perhaps you’re really interested in being as productive as possible, and for that reasons, skipping breakfast is more conducive to your goals. Then Obviously have family constraints that kind of thing too.

One thing that I was curious about your input was on whether you would transition people gradually into a restricted eating period. Or have them jump into it straight away. Just before I get your response to that, one more thing is [00:42:30] if people are eating less when they restrict their eating period, then that’s not always actually a good thing. Sometimes someone is actually trying to gain weight, in those circumstances, time restricted eating might not be optimal.

Likewise, if you’ve got someone who historically has had reproductive issues or something like that, which are particularly adversely affected by negative energy balance. Then that’s also something worth considering.

Anyway, back to the question, Jeff, how wold you transition [00:43:00] someone into restricted eating period. Would you go full-force straight into it, or would you try and shifting one day at a time?

Jeff Rothschild:

Yeah, That’s a good question. Just briefly at your points about who its not appropriate for. I’m glad you mentioned that, because definitely if you’re an 18 year old football player, who’s trying to build muscles and gain 20 pounds of muscle in the off-season, this is probably not for you. It’s an option, but eating late at night might be a good thing. When I put into practice. I think in this case, this is one time where a hard and fast role, people tend to prefer that. [00:43:30] With time restricted eating windows, you don’t emphasize the food quality- I mean I certainly would still work with someone to get a good pillars of breakfast, lunch and dinner and so on, but what’s appealing to people about this, I think I’ve noticed is “OK, all I need to worry about is these 10 hours. I’m going to start it at 8:30, and I’m going to end at 6:30. That’s it.” People, I suppose you can creep the hours down gradually, but I think starting with these hard windows, its effective.

What I will do gradually, is little bit less often, but [00:44:00] if I want to work someone towards, eventually to 20 to 24 hour fast, eventually if I want to get them to go from dinner to dinner once a week. Some people can do really well with that, meaning fasting from dinner to dinner. Then I might say, “Okay let’s go 16 hours here, and let’s go 18 hours here.” And creep towards that. I do that less often, but some people will respond quite well to that.

Greg Potter:

One more thought was people with dysglycemia also might be advised to avoid time restricted eating, or just to consider it with some interpretation. [00:44:30] Just because one consistency among many studies seems to be that skipping breakfast does lead to greater variability in blood glucose to clean the afternoon and in evening. If you are predisposed to hypoglycemia or anything like that, then that’s probably worth considering.

Dan Pardi:

Good point. We’ve talked about whether or not to skip breakfast. I think we don’t have a clear indication that one should or shouldn’t, but the evidence suggests that breakfast is important. Now the questions [00:45:00] are, if you are to have the timing of that first meal creep up, but it doesn’t vary, in terms of its timing day by day, is that going to then create a situation that is metabolically healthy consistently for an individual. Does it have to be at a certain time of day? After a sleep period, more questions to address there, but so far, a breakfast seems like a it’s a good idea. We did talk about caveats too in terms of eating patterns and what that can look like.

We didn’t talk about lunch skipping. Having a big breakfast, then having either [00:45:30] no lunch or a small lunch, and then having a small dinner. There’s a variety of different options here that we could consider. I currently don’t practice anything consistent. When I wake up in the morning, and I’m not hungry, I will try to extend my window by taking in food later. Sometimes I have an appetite in the morning, and sometimes I don’t. I’ll have some coffee or tea, and then I’ll wait until I get hungry. That seems to make sense for me, because I’m always trying to listen to what my body is telling me about my hunger versus forcing it at a time where my body is telling [00:46:00] me something different.

That’s at least the approach I’m playing with, I wouldn’t necessarily recommend that to everybody, but I think it’s worth sharing. The other thing I play with is even if I have breakfast a little bit later, then sometimes I won’t get hungry until two or three in the afternoon. There’s times now I’m skipping, and I’m trying some exogenous ketones beta-hydroxybutyrate to keep me feeling cognitively sharp and suppress my appetite until dinner time. For me that seems like it could be a winning strategy in terms of getting breakfast [00:46:30] earlier in the day, but avoiding excess calories across the 24 hour period by allowing me to wait a little bit longer till I have, hopefully an early dinner.

That’s two things that I’ve been playing with. Greg, do you do any sort of fasting yourself?

Greg Potter:

I do, periodically, particularly around the holidays, if I have a bit of a blow out day, maybe it’s Christmas or something like that, then I think shortly afterwards actually going in and doing a 24 hour fast is useful. More than anything, I do it for psychological reasons, just because [00:47:00] I think we get to appreciate that we’re fortunate to have all these food around, and also there’re potential benefits to which we haven’t spoken about today, but whether it’s increasing your [inaudible 00:47:11]tophogy or variety of other thing. Then that can be an useful practice, but also on a more routine basis, I do eat in a very consistent window. I wake up very early in the morning, about and hour afterwards begin my eating period, [00:47:30] keep it relatively consistently timed each day at about 12 hours. I just try to keep that as consistent as possible and obviously from time to time. Life gets in the way, or you go out on the weekend, or you go out for food in the evening with friends and that changes things. When I have more control over things, I do try to emphasize keeping timing as consistent as possible.

Dan Pardi:

How about in terms of what your meals look like? Do you have a big breakfast and a light dinner or is it balanced across three meals? Tell us about that.

Greg Potter:

[00:48:00] I eat a lot. So I eat four relatively big meals each day. Typical breakfast, what did I have this morning, I had half a kilo of natural yogurt, with a melon. Lots and lots of nuts. That’s relatively normal meal size for me. If anything, I think I go for a slightly bigger breakfast, and then the final meal of the day, because I have goals related to body composition, and also to training. I try to make sure that I [00:48:30] consume lots of protein, and preferably lots of relative slowly digestive proteins in that final meal to try and maintain muscle protein synthesis as long as possible overnight.

Dan Pardi:

Your strategy with the goal of both maintaining lean mass and also keeping your body fat lower. And Jeff, I know that you mostly eat when it’s light out. Is that still what you do?

Jeff Rothschild:

Yeah. For probably five or six years I’ve tried to aim with that general goal. I’ve pretty much always make an effort to eat [00:49:00] breakfast. Sometimes it’s 6:30 in the morning which is earlier than I might prefer, but if I have to be out of the house, I feel it’s that important to how well I feel through the day. My consistency in hunger and things like that. I used be a little bit stricter eating between an eight and eleven or eight to twelve hour window the last six months, I loosened that up, ’cause I’ve been training for an Iron man Triathlon. If we think in terms of the stress bucket, we have the stress bucket that could be work stress, family stress or lack [00:49:30] of food stress, or training. When the training stress goes up, I don’t want to also stress my body that much by going to bed hungry or, I mean I still don’t have a late night snack, but I might eat dinner or eat something as late as 7:00 or 8:00, sometimes 8:30.

Dan Pardi:

Great, Thank you guys, there’s so much more to discuss about fasting. We tried to put some borders on it, just so that we could focus a little bit more on some of the ideas that are generated simply off of breakfast skipping, but as you’ve heard, you could skip lunch, you [00:50:00] could have smaller dinners, or bigger dinners, eating patterns matter. There’s other health benefits that are a part of fasting as well. There’s other benefits of what composition of your breakfast look like. There’s different goals. It’s complex, but the work is promising, particularly around just metabolic health and weight regulation. Some of the most interesting aspects is that people report improved sleep and improved energy and are able to lose weight and maintain it. That was from the Satchidananda Panda study with first author is Gill. I’m excited to see some of the things we’ve brought up today and explore [00:50:30] it more in depth.

Thank you gentlemen for your time, and your expertise, and contributions. I look forward to having you both on the show again to explore the subject further. You guys have a great day, both of you.

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Recently, I wrote an article entitled Reducing stress in the hypothalamus – is this the best way to decrease body fat? In that article, I discussed how inflammation of the brain’s body-fat regulator – or ‘fat thermostat’ – is of critical importance for weight management. In this article, I discuss how certain dietary patterns affect inflammation in the fat thermostat, as well as short-and-longer term outcomes of different diet types.

It was traditionally thought that total brain blood flow was not changed during physical activity. Research in the last 10 years, however, changed this perspective. We now understand that the increased neuronal and metabolic activity of the brain during exercise drive increases in blood flow to it. We have also learned that exercise that is too intense will reduce blood flow and oxygen delivery causing fatigue. So, what is the ideal intensity to stimulate blood flow to the brain, and perhaps, augment your mental abilities in the moment?

When we think of foods that improve athletic performance, chocolate is maybe not one of the first options that comes to mind.

We’ve known for a while that certain molecules found in chocolate, known as flavonols, are associated with health benefits to the heart and the brain. Epicatechin, in particular, has exhibited widespread effects throughout the body.

But some emerging evidence suggests that chocolate may also aid in exercise performance – weird as it may sound.

Around this time of year, much of the world is advancing their clocks by one hour to make efficient use of seasonal daylight. Americans switched to Daylight Savings Time last week, and this week Europeans will revert to Summer Time.

When this happens, we all “lose” an hour of sleep, because we have to get up and get things done an hour earlier than we have been. This is in relation not just to the light and dark cycles of the day, but also to our body clocks.

One hour sounds like a small change, but it can make a big difference in how we function, at least in the short term. For example, data from the past two decades shows that there is a statistically significant spike in the number of car wrecks on the Monday immediately following the shift to Daylight Savings Time in the US.

As we all adjust to the time change, it’s worthwhile to consider how other aspects of our lives can sway our circadian rhythms. Circadian clocks govern the rhythms of sleep and activity in virtually all animals and are responsive to a variety of stimuli like light and stress. Research is starting to suggest that our eating patterns – specifically when we eat – can also have a pervasive impact.

We do not enter into the world with infinite knowledge of ourselves and our surroundings. We don’t have knowledge or skill to survive, to dance, or to do martial arts with grace and efficiency. We don’t know enough about ourselves or know how to interact best with different types of people we encounter. We don’t know how to accelerate our ability to get better at something. We are born, however, with the capacity to learn and to remember, and by virtue of this skill, we have an incredible potential to do great things.

Professor Marcos FrankToday, important stuff happened to you. Tonight, when you sleep, your brain will extend the process of turning that stimulation – the sites, sounds, thoughts, emotions, facts, etc. – into memories that you can access at a moments notice in the future. It’s amazing when you think about it: experiences, facts, skills, and even thought patterns become a part of who we are. How much do you know now that you didn’t know 1o to 15 years ago, or even last week, last month, or yesterday? The process of accumulating information, and accessing when needed, is so routine it’s easy to forget that something is going to make it possible. As it turns out, sleep plays a vital role in the formation of certain types of memories. In this interview, I speak with someone who has made, and continues to make, significant contributions to help the world better understand how all this magic works. My guest is Marcos Frank, Ph.D., who is the Interim Chair of the Department of Biomedical Sciences in the Elson S. Floyd College of Medicine at Washington State University. I hope you enjoy this discussion as much as I did.